The year was 1972; the place, suburban Springfield, New Jersey. One September day, a bizarre murder shattered the town’s sense of safety, and set in motion a cult-tinged mystery that’s become a local legend—and now, the subject of a new true-crime book.

It started with a string of inexplicable occurrences. Footprints in the snow coming from the woods to the back door, but not leading back; creaking in the attic; an unfamiliar newspaper in the kitchen. Then house keys went missing, and someone tried to break the lock on the tool shed.